GHSA-pwf7-47c3-mfhx is a critical-severity (CVSS 9.9) remote code execution vulnerability in j178/prek-action. A fix is available for j178/prek-action — see the affected versions and patch details below.
j178/prek-action vulnerable to arbitrary code injection in composite action
Real-World Exposure
j178/prek-actionReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects GitHub Actions packages — download data is not available via public APIs for these ecosystems.
Description
Summary
There are three potential attacks of arbitrary code injection vulnerability in the composite action at action.yml.
Details
The GitHub Action variables inputs.prek-version, inputs.extra_args, and inputs.extra-args can be used to execute arbitrary code in the context of the action.
PoC
- uses: j178/[email protected]
with:
prek-version: $(printenv >> $GITHUB_STEP_SUMMARY && echo "0.2.2")
extra_args: '&& echo "MY_SECRET with a character is: ${MY_SECRET:0:1}a${MY_SECRET:1}" >> $GITHUB_STEP_SUMMARY && echo ""'
env:
MY_SECRET: ${{ secrets.MY_SECRET }}
The previous example will print all the environment variables, and it will expose MY_SECRET environment variable value to the summary of the workflow. An attacker could potentially use this vector to compromise the security of the target repository, even passing unnotice because the action will run normally.
Impact
Critical, CWE-94
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦GitHub Actions | j178/prek-action | all versions | 1.0.6 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for j178/prek-action, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update j178/prek-action to 1.0.6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-pwf7-47c3-mfhx is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-pwf7-47c3-mfhx can be triaged on real exposure rather than presence alone.
Tailored to GHSA-pwf7-47c3-mfhx. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-pwf7-47c3-mfhx in your dependencies?
O3 Security finds GHSA-pwf7-47c3-mfhx across GitHub Actions dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.